package com.xiaochangwei.web.utils;

import java.security.MessageDigest;
import java.util.UUID;

/**
 * @since 2016年11月25日 上午10:25:27
 * @author 肖昌伟 317409898@qq.com
 * @description
 */
public class Encryptor {

	private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
			"e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y",
			"z" };
	private Object salt;
	private String algorithm;

	public Encryptor(Object salt, String algorithm) {
		this.salt = salt;
		this.algorithm = algorithm;
	}

	public String encode(String rawPass) {
		String result = null;
		try {
			MessageDigest md = MessageDigest.getInstance(algorithm);
			// 加密后的字符串
			result = byteArrayToHexString(md.digest(mergePasswordAndSalt(rawPass).getBytes("utf-8")));
		} catch (Exception ex) {
		}
		return result;
	}

	public boolean isPasswordValid(String encPass, String rawPass) {
		String pass1 = "" + encPass;
		String pass2 = encode(rawPass);

		return pass1.equals(pass2);
	}

	private String mergePasswordAndSalt(String password) {
		if (password == null) {
			password = "";
		}

		if ((salt == null) || "".equals(salt)) {
			return password;
		} else {
			return password + "{" + salt.toString() + "}";
		}
	}

	/**
	 * 转换字节数组为16进制字串
	 * 
	 * @param b
	 *            字节数组
	 * @return 16进制字串
	 */
	private static String byteArrayToHexString(byte[] b) {
		StringBuffer resultSb = new StringBuffer();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));
		}
		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0)
			n = 256 + n;
		int d1 = n / hexDigits.length;
		int d2 = n % hexDigits.length;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String generateSalt() {
		return UUID.randomUUID().toString().replace("-", "");
	}

	public static String generateEncodePasword(String salt, String password) {
		Encryptor encoderMd5 = new Encryptor(salt, "sha-256");
		return encoderMd5.encode(password);
	}

	public static boolean pswdIsCorrect(String password, String encodePasswod, String salt) {
		Encryptor encoderMd5 = new Encryptor(salt, "sha-256");
		String passwordEncode = encoderMd5.encode(password);
		return passwordEncode.equals(encodePasswod);
	}

	public static void main(String[] args) {
		for (int i = 0; i < 2; i++) {
			String salt = UUID.randomUUID().toString().replace("-", "");
			Encryptor encoderMd5 = new Encryptor(salt, "sha-256");
			//int random = (int) ((Math.random() * 9 + 1) * 100000);
			int random = 123456;
			String encodedPassword = encoderMd5.encode(String.valueOf(random));
			// System.out.println("加密后密码：" + encodedPassword + "\n密码长度：" +
			// encodedPassword.length());
			// System.out.println("salt:" + salt + "\nsalt长度：" + salt.length());
			System.out.println("random:" + random + "	,salt:" + salt + "	,encodedPassword:" + encodedPassword);
		}
	}

}